V. Principles of Operation
Kooltronic Air Conditioners are required when the equipment operating temperature must be kept near or
lower than the ambient room temperature, and/or the cabinet must be sealed from dust, fumes, oil,
corrosives and other contaminants. These Air Conditioners utilize a "Closed-Loop Cooling System" to ensure
optimum performance of the installed components.
Closed-Loop cooling seals the electronic enclosure from hostile elements in the environment. Two separate
circulation systems are employed. The internal system cools and dehumidifies the air inside the cabinet,
totally isolating the sensitive electronics and other components from the environment. The external system
uses circulating ambient air or water to discharge the heat removed from the electronics. The heat is
dissipated from the enclosure by means of the vapor compression refrigeration cycle. This takes place in a
hermetically-sealed refrigeration system, utilizing either an air-cooled or water-cooled condenser heat
exchanger. The warm air inside the enclosure is drawn through the evaporator coil where it is cooled,
dehumidified and returned.
The heat removed through the evaporator coil is transferred by the compressed refrigerant to the condenser
coil. Ambient air or water is then passed through the condenser coil, where it absorbs the heat and is then
discharged to the environment.
The unit is equipped with a Low Temperature Thermostat to prevent the evaporator coil from freezing and
must not be set below the factory setting of 75°F (16°F differential). If necessary the thermostat may be
adjusted to increase the temperature within the cabinet. Unlike thermostats that are commonly found in
household air conditioners that control the room temperature, the thermostat found on the EP56 monitors
the return air from the enclosure to prevent the evaporator from freezing. In conditions of low ambient
temperature and low enclosure load, the thermostat regulates the return air temperature from 75°F to 91°F.
If the unit is equipped with an optional non-adjustable high temperature alarm, it will activate when the
temperature reaches 130°F. A condenser blower thermostat is standard on this unit. The thermostat
temperature sensor is installed in the refrigerant liquid line. When the ambient temperature is above 95
o
F the
condenser fan will run at full speed. When the ambient temperature is lower than 95
o
the condenser fan will
cycle. In applications having frequent voluntary heat load fluctuations, an optional Compressor Short Cycle
Protector is recommended.
When the Kooltronic Air Conditioner is properly sized it should operate constantly and maintain 75
o
F to
115
o
F enclosure temperatures, depending on the ambient temperatures.
ENCLOSURE AIR
OUT
CONDENSER AIR
IN (3 PLACES)
ENCLOSURE AIR
IN
CONDENSER AIR
OUT
EP56TR
5
